Do Filtered Statistics update as frequently as normal statistics?

I received a question this week about whether filtered statistics update as frequently as regular statistics.  The right way to ask the question is “Do filtered statistics become invalid as frequently as regular statistics?”, as stats are recomputed based on the queries that consume them, while stats are invalidated based on changes to the underlying…

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SQL Server 2008 Internals Book Now Available!

For those of you waiting for the new "Inside SQL Server" book, it is actually out now.  Kalen decided to give it a name change, and the actual title is "SQL Server 2008 Internals".  I’ve written a chapter on how the Query Optimizer works.  It is currently #1 in the 3 related database/sql server categories…

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Conor vs. Isolation Level Upgrade on UPDATE/DELETE Cascading RI

A customer recently asked our support organization about an unexplained series of range locks that they were seeing on a DELETE to a table with a foreign key. Here is the repro:   1: create table Foo (FooId int not null primary key) 2: create table Bar (FooId int not null, BarId int not null)…

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Conor vs. Indexed View Updates

(as ANSI NULLs is one of the requirements for indexed views, I thought I’d give you some perspective on why the questions I ask you are useful and interesting to better understand queries and various query operations)   As currently designed, indexed views tries to strike a balance among: 1. query shapes that can be…

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Conor vs. Non-ANSI NULLs, part 1

I was thinking about indexed views.  Well, more specifically, I was thinking about why indexed views are hard to use.  One of the reasons that they are hard is that there are just so many restrictions.  Anyways, one of the things I’d like to better understand is how many customers actually use ANSI NULLs OFF…

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Conor vs. MERGE and PRIMARY KEY collisions

MERGE is a new operation added in SQL Server 2008. It has all sorts of knobs, bells, and whistles. The primary value of this feature is to collapse multiple query statements into one query statement. Overall, this avoids the “overhead” necessary to run a query a few times and can be a big benefit, especially…

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Conor vs. His Printer

As many of you may know, I work from my house most of the time – I have a nice office that is quiet and I actually find it to be a great way to get stuff done – I have no commute, I don’t get interrupted very much, and I have to attend fewer meetings…

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OPTIMIZE FOR UNKNOWN – How could that possibly make any sense???

Yes, I’m alive. I have been chatting with my wife about the times I need to “go dark” – in this case, I am working on features that I can’t discuss yet, other than to say that I am *very* excited to go to work every day.. (well, since I work out of my house,…

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